Gonorrhea is a sexually transmitted disease (STD), caused by Neisseria gonorrhoeae, which commonly infect the epithelium cervix (cervicitis), urethra (urethritis), rectum (proctitis), and conjunctiva of eye (conjunctivitis). Gonorrhea if left untreated can lead to complications such as periurethritis and epididymitis in men, endometritis, salpingitis, abscess (in Fallopian tubes and ovaries), bartholinitis, peritonitis, and perihepatitis in women and ophthalmia neonatorum in newborns infants.

Global scenario of gonorrhea:

Gonorrhea is still a major public health problem in most parts of the world and a major cause of morbidity in developing countries. Gonorrhea may play a role in transmission of HIV infection.

Plague is acute febrile disease due to infection of Yersinia pestis. Plague is one of the most virulent bacterial infections known to occur in humans, although completely curable by appropriate antibiotics. If not treated with appropriate antibiotics the case fatality rate of plague is very high.

Types of plague:

There are three clinical types of plague namely bubonic, septicemic, and pneumonic plague.

Transmission of Plague:

Plague is transmitted by most commonly by bite of flea infected with Yersinia pestis. Plague can also be transmitted by direct contact with infected materials (such as animal tissue) and by droplet infection, as in case of pneumonic plague.

If there is outbreak of Yersinia pestis among rodent hosts, the rodents die in large numbers and infected fleas in search of new host bite humans to cause plague.

Constipation is a common health problem, especially in the Western world, most probably due to dietary habits and lifestyle. It is difficult to define constipation, due to wide range of normal bowel habits, but in general constipation refers to persistent, difficult, infrequent, or seemingly defecation.

The normal stool frequency also has a wide range, e.g. in Western countries most individuals have at least 3 bowel movements per week, but in developing countries an individual may have as many as three bowel movements per day (due to consumption of natural food with high fiber content) as normal bowel habit. If an American or European has 3 bowel movements a day it can be considered as diarrhea and if an Indian (or from other developing country) has 3 bowel movements per week it can be considered as constipation.That is why low stool frequency alone can not be the sole criterion for the diagnosis of constipation and other factors need to be considered before diagnosing constipation.

Before the discovery of the mode of transmission by Aedes aegypti mosquito in 1900 the Yellow fever was causing major epidemics in the Americas (North America and South America), Africa, and Europe. Despite the availability of an effective and safe vaccine for yellow fever, several hundred jungle yellow fever cases occur in South America every year, and thousands of jungle as well as urban cases of yellow fever occurs each year in Africa.

What is the causative agent of Yellow fever?

Yellow fever is caused by Yellow fever virus, a flavivirus. Yellow fever virus belongs to Flaviviridae family.

How yellow fever is transmitted?

Yellow fever is commonly transmitted by bite of Aedes aegypti mosquito. An urban cycle and a jungle cycle or sylvatic cycle (in Africa) of yellow fever virus exist, which involve Aedes mosquitoes and monkeys. Aedes aegypti mosquito is originally an African species, but has spread to other parts of the world.

West Nile Fever is seen in Africa, southern Europe, the Middle East, and in some parts of Asia. Lately West Nile Fever is spreading in other parts of the world, e.g. in the year 1999, the disease was introduced in New York City and spreading in other parts of the United States subsequently, especially in many of the northeastern states of United States. The West Nile Fever, after introduction in the New York City has caused several cases of aseptic meningitis and/or encephalitis among humans. The West Nile Fever virus is also causingserious problems among crows, exotic zoo birds, and other birds in the northeastern states of United States. The virus is also spreading and already spread to neighbouring Canada and Mexico. In the United States approximately 1000–3000 cases of encephalitis occurs (due to West Nile Fever virus) annually with approximately 100–300 deaths.

What is the causative agent of West Nile Fever?

West Nile Fever is caused by West Nile virus. The West Nile Fever virus belongs to phylogenetic group of flaviviruses, the same group of virus which cause St. Louis encephalitis and Japanese encephalitis, Murray Valley fever and Rocio fever.

Psoriasis is one of the most common skin diseases and affects approximately 1% (one percent) of the world population. Psoriasis is a chronic inflammatory disorder of skin.

Different varieties of psoriasis:

There are several different varieties of psoriasis such as plaque type (the most common variant of psoriasis), inverse psoriasis, guttate psoriasis (also called eruptive psoriasis) and pustular psoriasis.

Plaque type psoriasis:

This is the most common variant of psoriasis. The plaques of plaque type psoriasis remain stable for long time (plaques enlarge very slowly). The plaques of psoriasis are most commonly seen on elbow, knee, scalp and gluteal cleft. The lesions are generally symmetric. Remission occurs very rarely in plaque type psoriasis.

Atopic dermatitis (or atopic eczema) is characterized by a family history of asthma, allergic rhinitis, eczema and it is cutaneous expression of the atopic state. The numbers of cases of atopic dermatitis or prevelance of atopic dermatitis are increasing all over the world.

What is the etiology of atopic dermatitis?

The etiology of atopic dermatitis is not well defined and there is certainly a strong genetic cause, because if both paretnts are affected by atopic dermatitis, the risk of children developing atopic dermatitis is more than 80%. When only one patrent is affected by atopic dermatitis the risk of children developing atopic dermatitis is approximately 50%.

Measles is also called rubeola, which is a highly contagious, acute, exanthematous respiratory disease. The characteristic clinical features and have a pathognomonic (the word pathognomonic means a clinical feature seen only in that particular disease and not in any other disease) enanthem, known as Koplik's spots (which are white or bluish lesion with an erythematous halo on the buccal mucous membranes).

Measles still continues to be a major cause of mortality and morbidity among children in many developing countries, despite availability of a highly effective vaccine. The measles vaccine, which is highly effective, is available since the year 1963. Measles is only sporadically seen in most of the advanced and industrialized countries, due to extensive use of measles vaccines as part of Universal Immunization.

Xerophthalmia or “dry eye” is a condition of the eye, where the eyes do not produce enough tear and eyes become dry. Xerophthalmia is derived from Greek word means dry eye ("xeros" means dry and "ophthalmos” means eye so xerophthalmia means dry eye). Xerophthalmia represents all the ocular manifestations of deficiency of vitamin A in man, from mildest form night blindness to gravest keratomalacia, which is an ocular emergency.

How common is xerophthalmia?

Xerophthalmia is the most common nutritional disorder that affects the eye. Xerophthalmia is a disease of developing countries and accounts for up to 100,000 new cases every year in developing countries and many of these new cases ultimately cause blindness. Xerophthalmia is commonly a disease of childhood and generally affects children between 1-3 years of age and mainly seen below 9 years of age. Xerophthalmia is related to weaning of children and the younger the child the serious is the problem and complications. Xerophthalmia is common in Africa and Southern Asia, but rare in most of the developed and industrial countries. Xerophthalmia may be associated with PEM (protein energy malnutrition) and can be fatal if associated with PEM among children between 1-3 years of age which commonly affects the poorest families.

What is Urinary Tract Infection?

Acute infection of urinary tract by bacteria is UTI (urinary tract infection). Presence of pathogenic microorganisms (mainly bacteria) in urine, urethra, urinary bladder, kidney, or prostate is urinary tract infection. Urinary tract infection may be lower urinary tract infection or upper urinary tract infection. Lower urinary tract infection includes urethritis (infection/inflammation of urethra) and cystitis (infection/inflammation of urinary bladder) and upper urinary tract infection includes acute pyelonephritis, prostatitis (infection/inflammation of prostate gland) and intrarenal and perinephric abscesses.